Deeper understanding of asthma uncovered

A study into asthma has led to a ‘paradigm shift’ in the understanding of condition, academics have claimed.

The research by the University of Leicester, England, has led to the discovery that increased amounts of a protein called PP5 in the lungs of severe asthma patients blocks the effects of the best medicines.

Understanding the mechanisms behind the abnormal expression of PP5 in severe asthma could lead to novel treatments, says Dr Yassine Amrani, associate professor in respiratory immunology and lead study author.

Writing in Allergy, the team describe how they first performed test tube experiments using cells from healthy and severe asthma patients isolated using bronchoscopy to identify the proteins that interfere with corticosteroids in the lungs.

They also looked at whether or not these inhibitory proteins were abnormally expressed in the lungs of patients with severe asthma.

Dr Amrani said: “The study demonstrated for the first time that a protein called PP5 was significantly upregulated in the lungs of severe asthmatic patients compared to healthy controls. The test tube study allowed us to show that this protein was playing a key role in suppressing the anti-inflammatory action of corticosteroid, thus identifying this protein as a potential new player in reducing patients’ response to corticosteroid therapy.

“Previous studies by experts in this field have provided some possible mechanisms but were done mostly in non-lung cells.

“The originality of our work is demonstrated in that the blunted response to therapy in severe asthma may derive from a reduced sensitivity of key lung structural cells such as the airway muscle tissue which is responsible for the acute asthma attacks via their ability to narrow the airways. We provide evidence that the airway muscle tissue behaves like an inflammatory cell that is capable of producing different asthmatic factors known to be involved in severe asthma.”

Chachi L, Abbassian M, Gavrila A, et al. Protein phosphatase 5 mediates corticosteroid insensitivity in airway smooth muscle in patients with severe asthma. Allergy October 2016; doi: 10.1111/all.13003.